In recent years, the popularity of sport utility vehicles has risen tremendously. Because of the high ground clearance of these vehicles, the vehicle floor level is higher than that of a typical passenger automobile. Some individuals have experienced difficulty entering and exiting sport utility and similar high ground clearance vehicles.
Running boards have been used to assist passengers in entering and exiting high ground clearance vehicles. The conventional running boards have typically included a variety of stationary step or bar structures rigidly mounted to the vehicle. Stationary running boards have many disadvantages, however. For example, if a stationary running board is positioned at an optimum height to help most passengers, the stationary running board reduces ground clearance of the vehicle. If the stationary running board is positioned so that desirable ground clearance is maintained, the stationary running board is too high to help most passengers enter or leave the vehicle. Stationary running boards also detract from the vehicle styling, undesirably increase the vehicle width, and may even increase the vehicle width beyond the legal limit. Most stationary running boards are also very narrow in the transverse or cross-vehicle direction and present only a small stepping surface for a passenger's foot.
The patent literature has proposed various retractable vehicle running boards in order to resolve some of the problems associated with stationary running boards. For example, U.S. Pat. No. 3,762,742 proposes to provide a step that is pivoted about an axis that is angled in an outboard direction as it extends upwardly. While such angling of the pivotal axis enables the running board to be positioned closer to the ground when deployed in comparison to its position when stored, the optimum running board positioning in the two positions is not achieved. In addition, many of the proposed retractable running boards, such as that disclosed in the aforementioned '742 patent, do not provide the moving mechanical parts of the retractable running board with effective protection from the environment or from damage caused by dirt and other objects thrown by the vehicle wheels when the vehicle is moving.
More particularly, on four door sport utility vehicles the lower edge of the door is contoured to as a result of the position of the rear wheel well. A running board as shown in the prior art would be positioned too far forward and would thus be of little assistance on entering the rear door.
Furthermore, several of the proposed mechanisms for powered retractable running boards, including the aforementioned '742 patent, do not provide a means for retracting the step from the deployed position in the event of a power failure, or for preventing damage to the step in the event that the deployed step forcibly encounters an object.